Effects of an exercise program on calf muscle characteristics in patients with Achilles tendinopathy.
Merve Karapınar, Hayley Powell Smitheman, Stephanie Grace Cone and 1 others
PMID 41061600WHAT IT FOUND
A 16-week progressive exercise program improved calf muscle quality and size in patients with Achilles tendinopathy.
Echo intensity dropped 8-13% and muscle cross-sectional area increased 5-7%. However, these structural changes did not predict improvements in functional performance like jump height.
Key findings
01Muscle echo intensity decreased significantly in the gastrocnemius muscles, exceeding the minimal clinically important difference.
02Heel-rise work improved on the symptomatic side, but jump tests did not change.
03Changes in muscle structure did not explain the improvements in functional performance.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study was a secondary analysis of a larger trial, not a primary randomized controlled trial. Soleus measurements were limited to a small distal portion, potentially missing adaptations in the larger muscle compartments. Participants with bilateral symptoms were included, and the 'least symptomatic' side may have had subclinical pathology, complicating side-to-side comparisons. Exercise intensity and volume varied between participants based on pain levels, introducing heterogeneity. Pain levels were not systematically monitored during the intervention, which could have influenced functional performance outcomes.
Declared interests
Declarations of interest: None.
The easy way to misread this
Do not assume that improvements in muscle size or quality will lead to better functional performance like jumping. The study found no significant correlation between these structural changes and functional gains, and jump heights did not improve despite muscle adaptations.